vegas, wonderful young lady, who describes to me she's got 42 kids in her clas the first two weeks, she's got me of them sitting on the floor until finally, they get reassigned. they're using textbooks that are ten years old. >> when it comes to keeping america great, salman khan is a bit of an expert with an mba from harvard. he's dedicated himself to education. he's founder of the khan academy but his youtube channel has over 3,000 educational videos on everything from physics to history. his new book is titled "the one world schoolhouse." he's also on "time" magazine's list of 100 most influential people in the world. welcome. you are the most popular teacher in the history of planet earth. it's undeniable. the stats don't lie. is it four million people now watched your video lessons for want of a better phrase, right? >> that's right. seven million. we're not just videos, we have interactive exercises. it's not just me anymore. >> seven million people around the world will go online to see you give effectively a lesson. >> i give lessons, we have a few other folks who are doing it.